The major goal of this proposal is to use genetically defined animals to show how iron content in the brain is related to iron parameters in the periphery. The animal model to be employed in this research consists of a panel of recombinant inbred (RI) mouse strains, to refine the natural traits relating to high- and low-brain iron concentration. The mandate of this Core is to provide animals with phenotypic characteristics relating to brain iron concentration. Aim 1. To provide animals, animal tissue and support service for Projects #3 and #4. Aim 2. To maintain a colony of BXD inbred mice in order to refine the current phenotype or to explore other phenotypic characteristics that are identified in RLS subjects or autopsy material over the ensuing years of the Program Project. Aim 3. To perform quantitative genetic analysis on nigral brain iron content.